Circuit breaker



S. S. GRADY CIRCUIT BREAKER June 24, 1930.

2 Sheets-Shed 1 Filed Aug. 31, 1928 IN VEN TOR. ephen S. Grady AQ/WJ ATTORNEY.

I June 24, 1930. I s. s. GRADY 1,767,843

CIRCUIT BREAKER Fi led Aug. :51, 1928 2 Sheets-Sheet 2 IN VEN TOR.

: '75 5+ hen S. Grady.

35 BY ATTORNEY.

Patented June 24, 1930 UNITED STATES PATENT OFFICE CO., INC., A CORPORATION OF NEW YORK CIRCUIT BREAKER Application filed August 31, 1928.

This invention relates to circuit breakers in general and more especially to circuit breakers embracing an electric switch.

Among the objects of the present invention it is aimed to provide an improved construction of a switch controlled circuit breaker in which the switch can be operated manually to break the switch and on the other hand the switch automatically operated to break the circuit as a result of an overload.

More specifically the present invention aims to provide an improved switch controlled circuit breaker equipped with thermostatic means for automatically operating the switch to breakthe circuit in case of a light or gradually increasing overload'and equipped with electro magnetic meanswhereby the switch can be automatically operated to break the circuit in case of a sudden or heavy overload.

More particularly the present invention further aims to provide a circuit breaker for use in residences and the like associated with a lighting system or the like whereby after an overload has caused the circuit breaker to break the circuit, the same can readil be reset by the average layman or unskilled attendant, without the use oftools or the like.

These and other features, capabilities, and advantages of the invention will appear from the subjoined detail description of one specific embodiment of the present invention illustrated in the accompanying drawings in which Figure l is a plan view of a junction box partly broken away, equipped with a plu rality of the circuit breakers constituting the present invention;

Fig. 2 is an enlarged section on the line 2-2 of Fig. 1; c

Fig. 3 is an enlarged plan view of a single circuit breaker with a part of the housing removed;

Fig. 4 is a longitudinal section of a single circuit breaker illustrating the position of the several parts when the circuit has been broken and the unit has been removed from the unction box;

Fig. 5 is a similar longitudinal section of Serial No. 303,189.

an individual circuit breaker after the same has been reset in position to make a circuit;

a Fig. 6 is an enlarged detached side elevation of the latch member forming a part of the circuit breaker;

Fig. 7 is a transverse section on the line 77 of Fig. 4;

Fig. 8 is a transverse section on the line 8-8 of Fig. 5; and

Fig. 9 is a fragmental section on the line 99. of section 7.

In the present embodiment there is provided a supporting block 1 preferably com posed of insulated substance such as porce lain or fiber which is preferably provided with a recess 2 at one end of the block 1 and a recess 3 in alinement with said recess 2 at the other end of the block. The re cesses 2 and 3 constitute a pair for each set of connections or circuit breakers. If, as indicated in Fig. 1, the block 1 is provided with three circuit breakers there will necessarily be three pairs of recesses 2, 3. In the recess 2 there is secured a metal outer clip 4 having an opening in its li portion 5 to receive the screw 6 and a flexible jaw member "at its inner end. In the recess 3 there is secured a similar outer clip 7 having an opening formed through its lip portion 8 to receive the screw 9, which clip 7 is also provided with a flexible jaw member 10 at its inner end. The screw 6 in the resent instance is used to connect the terminal 11 of the conductor 12 through the lip portion 5, such screw 6 having its head portion resting against the terminal 11, and extending through the lip portion 5 and porcelain member 1 and terminating in the recess 13 where it receivesthe nut-14. Similarly the screw 9 extends through the terminal 15 of the conductor 16 which is separated from the conductor 12 by means of the circuit breaker to be described, the screw 9 extendin through the lip portion 8 into the porcelain portion 1 and terminating in the recess 17 where it receives the nut 18. When the conductors 12 and 16 are extended through conduits as illustrated in the present instance, the conduits for the'conductors 12 and 16 through such terminal 15' and then.

. STEPHEN S. GRADY, OF MAGNOLIA, NORTH CAROLINA, ASSIGNOB TO FUSOID ELECTRIC 4o ti a on which a met l n? which is preferably 4 pr ii two wing members 37 and which and in contact with such v' and 38 there is pivotally conn end 39 of the main switch knife 40, the pivot pin 41 extendin through 50 the wing members 37 and 38 and the end 39 of the switch knife 40. The metal member 36 is secured to the supporting portion of the insulated bony member 84 by means of the screw 42. The main body 55 portion of the switch knife 49 is disposed to operate in the main chamber 48 o f the insulated body member 34 and has secured thereto a lever 44 composed of an insulated material such as porcelain or fiber. Such lever in the present instance is secured to the en ension 45 of the switch blade 40, is provided with a recess at 46 and has an extended arm 47 extending over and beyond the edge of the switch blade 40. The lever 44 15 provided with two projections 48 and so described more in dea pressure on the the switch blade 40 if/55161011, th re is pro-- ends or which are In Fig. 4, the (re 46 are shown dcorealring position by g. 5, the lever 44 and 10 are hown raised in oppothe spring 50 being disposed in position and anchored in the latch member 54. The as particularly shown in consists of an arm memgated finger 56, a spur i nger 56 and a flat arm a angles to the finger 56 a recess 59 to form the The arm has pivotally conthe flapper 62 which m oy icreto oi titled with tail-piece 63. Between ivot pin 61 nd the arm 58 the arm provided with an opening 64. The 54 is floatingly mounted in the chanr 0 having the free end of the sprin extending through the opening 64, which lg 65 is secured between the metal memr 6 and the supporting portion 35 and .nercises a tension on the latch member 54 the same direction as the tension of the ring 50. The insulated body member 34 is provided with an opening 66. Preferably on the inside or the body portion 34 and disposed adjacent to such opening 66, there is provided a supporting plate 67 provided with an opening 68, see particularly Fig. 9. The plate 67 as shown in Fig. 9, is provided with a lip 69. The plate 67 1s also rovided with a recess 70 extending from t e opening 68 and an opposing recess 71 to receive the free ends 72, 73, and 74 of the U-shaped member 75. The arm 58 is adapted to extend through the opening 66 and into engagement with the lower inclined end 76 of the U-shaped member 75. In the operation of the device, the fin er 56 extends into the recess 92 of the bla e 40, the spur 57 extends into the orifice 77 of the blade 40 to engage the lower face 78 0f the blade 40 in the orifice 77 to maintain the blade 40 and lever 44 in circuit making position. The latch member 54 will be maintained in such raised position by the engagement of its shoulder 60 with the lip 69 of the plate 67, as shown in Figs. '7 and 8. A flat spring 79 is secured to the insulated body member 34 to exercise a tension on the arm 58 of the latch member 54 whereby the spur 57 "ccive the free en will be caused. to be depressed into the orifice 77 of the blade 40 and against the shoulder when the latch member 54- is permitted to extend outwardly after the circuit is broken into the position illustrated in Fig. 7 in which position, the spur 57 will be ready to engage the face 78 to raise the blade 46 when the U-shaped member 75 is pressed inwardly thereby engaging the latch member 54 and, pressing it inwardly. After a circuit is broken, and when the circuit breaker thereof is to be reset, it is merely necessary to remove the circuit breaker, engage the same so that the U-shaped memher 75 is pressed against an opposing surface until the latch member 54 has been raised sufliciently to permit its shoulder 60, to engage the lip 69, when the circuit breaker will be reset and be in position again to make a circuit after the circuit breaker is returned into engagement with the clips 4 and 7. When the U-shaped member 75 is so being pressed inwardly, the inclined end 76 will cooperate with the end of the latch member 54 to urge the same against the lip 69, see Fig. 9, until the lip 69 registers with the notch 59 whereupon the latch member 54 will snap into position where its shoulder 6O will engage the lip 69.

The insulated body portion is provided with two inner metal clips, the clip 79 and the-clip 80. The inner clip 7 9 is adapted to cooperate with the clip 4 and engage the same, and the clip 80, is adapted to be clamped into position by the clip 7. The inner clip 79, as particularly illustrated in Fig. 2, is provided with two clamping jaw members 81 and 82 adapted to receive the free end of the blade 40 in circuit making position, as illustrated in. Fig. 5, and to re- A 44 in the circuit breaking position, as shown in Fig. 4.

The inner clip 80 is electrically connected by means of the conductor of the electromagnet 84 which electrical conductor 83 then extends over to the free end 85 of the laminated U-shapcd thermostat 86, the other end of the U-shapedthermostat 86 bein connected to the free end of the arm 8 extending from the metal wing 38. The intermediate end of the thermostat 86 is provided with an insulated abutment piece 88, which see Figs. 3 and 8 isadapted to be disposed opposite to the finger 56 in circuit making position.

From the foregoing it will be seen that in circuit makingposition the current will pass from the conductor 12 through the outer clip 4, inner clip 79, blade 40, wing 38, arm 87, thermostat86, conductor 83, inner clip 80, and outer clip 7 to the conductor 16.

After the circuit breaker is in position to make circuit, then, in case of a light overload or of a gradually increasing overload,

the thermostat 86 will gradually heat up and warp, pressing the abutment 88 into en gagement with the finger As soon as the abutment 88 has sufiiciently pressed the finger 56 to cause the spur 57 to clear the surface 78 of the blade 40, the spring 50 will be free to snap the arm 44 and blade 40 into the chamber 43 thereby causing the blade 40 to clear the jaws 81 and 82 and cause the insulated arm 44 to engage such jaws 81 and 82 when the circuit will be broken.

On the other hand, in case of a" sudden overload or heavy overload, the current will cause the magnet to attract the flapper 62 whereupon it will cause the tail-piece 63 to press against the blade 40 to pry the latch member 54 away from the blade 40 until the spur 57 of the latch member 54 clears the surface 78 of the blade .40, when, again the spring 50 will be free to snap the arm 44 and blade 40 into the chamber 43 whereupon the blade 40 will clear the jaws 81 and 82 to break the circuit.

When the arm 44 and blade 40 are snapped into position to break the circuit, the U- shaped 'member 75 will still rest against the block 1, the light spring 65 not being strong enough to press the latch member 54 and U-shaped member 75 outward against the block 1. However, as soon as the circuit breaker has been removed from engagement with the outer clips 4 and 7 of the junction box, the spring 65 will be free so to press the latch member 54 and U-shaped member 75 outward into position where the circuit breaker is ready to be reset by merely exercising pressure on the U-shaped member 75 until, as aforesaid, the latch member 54 has been pressed inwardly sufficiently to have its shoulder 60 again engage the lip 69. During such inward movement of the latch member 54, as aforesaid, the spring 79 exercising outward tension on the arm 55 of the latch member 54 will cause the spur-'57 of the latch member 54 to engage the surface 78 of the blade 40 so that the blade 40 and arm 44 will be reset against the tension of the spring 50 simultaneously with the resetting of the latch member 54.

'The circuit breaker is also provided with a cover member 89 which is provided with two openings 90 and 91 to register with the projections 48 and 49 respectively of the arm 44. When the circuit breaker is in cir cuit making position, the outer surface of the projections 48 and 49 will be substantially flush with theouter surface of the cover 89 and will be clearly seen as for instance in the left hand circuit breaker of the two shown in Fig. 1. On the other hand, when the circuit is broken and the arm 44 is swung inwardly away from the cover member 89, such projections will be depressed, and not be readily visible, see for broken, and -means for-ope'rativelymonnecting said latch when in protruded position with said blade so that the return of said latch into said housing into latch anchoring position will in turn return said blade into circuit making position.

6. A circuit breaker comprising a pair of terminals, a stationary contact operatively associated with one of said terminals, a switch blade pivotally connected at one end and adapted to engage said contact in circuit making position, a spring operatively connected to actuate said blade-into circuit breaking position, a latch for anchoring said blade in circuit making position against the tension of said spring, overload detecting means operatively connecting the other end of said blade with the other terminal said detecting means being-operative to tri said latch in case of an overload to perm1t said spring to snap said blade into circuit breaking position, an insulated body member associated with said circuit breaker, therebeing an opening in said bod memher, a second spring for causing said latch to" protrude from said opening after a circuit has been broken, and means for opera-' tively connecting said latch when in protruded position with said blade so that the return of said latch into said housing into latch anchoring position will in turn return said blade into clrcuit making position, said latter operative means also serving as a fulcrum to facilitate tilting said latch out'of anchoring position.

7. A circuit breaker comprising a pair of terminals, a stationary contact operatively associated with one of said terminals, a switch blade pivotally connected atone end and adapted to engage said contact in circuit making position, a s ring operativel connected to actuate said blade into circuit breaking position, a floatable latch for anchoring said blade in circuit breaking position against the tension of said spring, overload detectinglmeans o )eratively connecting the other end of said blade with the other terminal, said detecting means being operative to trip said latch in case of an overload to permit said spring to snap said blade into circuit breaking position, and means for guiding said latch.

8. A- circuit breaker comprising a pair of terminals, a stationary contact operatively associated with one of said terminals, a

switch blade pivotally connected at one end and adapted to engage said contact in circuit making position, a spring operatively connected to actuate said blade into circuit breaking position, a floatable latch for anchoring said blade in circuit breaking'position against the tension of said spring, overload detecting means 0 eratively connecting the other end of said: lade with the other terminal, said detecting means being opera tive to trip said latch in case of an overload to: permit said spring to snap said blade into circuit breaking position, and insulated body member associated with said circuit breaker, there being an opening in said body member, a second spring for causing said latch to protrude from said opening after a circuit has been broken, and'a third spring for urging said latch when in protrude position into engagement with said blade so that the return of said latch into said housing into latch anchoring position will 1 in turn return said blade into circuit making position, said second spring, third spring, and the edges of said opening coopcrating with one another to guide said floatable latch in its several operative positions.

STEPHEN s. GRADY. 

